Paolo Berzaghi

Investigation of a LOCAL calibration procedure for near infrared instruments

A new procedure (LOCAL) for local calibrations is presented. LOCAL selects spectra from a library of samples and computes a PLS calibration equation for each constituent of the sample. This study evaluated the performances of LOCAL on the prediction of ground corn grain and haylage using several different combinations of data transformations, wavelength segment reduction, number of PLS factors and samples used in calibration. LOCAL resulted in lower SEP values for all the constituents of corn and dry matter of haylage with improvements ranging between 6 to 13%. Global calibrations had only a small advantage over LOCAL (1–2%) in the prediction of acid detergent fibre and crude protein in haylage. The two most important variables controlling the accuracy of predictions were number of samples in the calibration and number of PLS factors in the solution. Best results were obtained using 150 to 225 samples and more than 20 PLS factors per calibration equation. The speed of the LOCAL procedure is 0.5–2 s per sample on a 90 MHz computer. With this speed and accuracy, LOCAL is now available for real-time routine operation on a Windows platform.

LOCAL prediction with near infrared multi-product databases

This study evaluated the use of an algorithm (LOCAL) for local calibration using multi-product databases. Four different databases were used: forages (hay, corn silage, haylage, small grain silage and total mixed ration; n=2924), grain (barley, corn, oats and wheat; n=1464), meat (meat and bone meal, fish meal and poultry meal; n=693) and feed (bakery products, mixed feed, poultry feed and soya products; n=1518). One-tenth of the samples were selected for validation from each database. Predictions of validation samples using generic and specific global calibrations were compared to the predictions generated by LOCAL. Standard errors of prediction for LOCAL calibrations were always lower than those of generic global calibrations and similar to those of specific global calibrations. However, LOCAL predictions were further improved by using different settings for each constituent. The analysis of the samples selected by LOCAL showed that for heterogeneous products such as total mixed rations and corn silage, LOCAL optimised predictions by choosing samples from different products. LOCAL calibration was then used with one database (n=6599) comprising all the samples. Standard errors of prediction were similar to those obtained with the four different databases. LOCAL can accurately predict the composition of different products using multi-product databases. Routine analysis can be simplified by using LOCAL calibration combined with large databases. In addition, LOCAL can provide accurate predictions of spectra from remote standardised instrument without the operator identifying the sample.

Discrimination between Shiraz Wines from Different Australian Regions: The Role of Spectroscopy and Chemometrics

This study reports the use of UV-visible (UV-vis), near-infrared (NIR), and midinfrared (MIR) spectroscopy combined with chemometrics to discriminate among Shiraz wines produced in five Australian regions. In total, 98 commercial Shiraz samples (vintage 2006) were analyzed using UV-vis, NIR, and MIR wavelength regions. Spectral data were interpreted using principal component analysis (PCA), linear discriminant analysis (LDA), and soft independent model of class analogy (SIMCA) to classify the wine samples according to region. The results indicated that wine samples from Western Australia and Coonawarra can be separated from the other wines based on their MIR spectra. Classification results based on MIR spectra also indicated that LDA achieved 73% overall correct classification, while SIMCA 95.3%. This study demonstrated that IR spectroscopy combined with chemometric methods can be a useful tool for wine region discrimination.

Effects of feeding propylene glycol to mid-lactating dairy cows

Propylene glycol (PG) is a gluconeogenic precursor widely used to prevent and treat ketosis postpartum. The study has investigated the effects of PG administration to dairy cows at mid stage of lactation. According to a 3 × 3 latin square design, three Italian Brown lactating cows (125 ± 7 days in milk) fitted with rumen cannula were fed a corn silage based diet (CP 14.7%, NDF 41.1% DM) with 0, 200 or 400 g day−1 PG added. Dry matter intake was increased by feeding PG with a significant quadratic component per dose (16.2, 17.2 and 16.5 kg day−1 for 0, 200 and 400 g PG day−1, respectively). Milk yield was not affected by PG, averaging 17.1 kg day−1. Average daily gain increased from 64 to 206 and 302 g day−1 when cows received 200 and 400 g day−1 of PG (linear component per dose P < 0.05). Digestibility of the diet did not differ among treatments, whereas repeated rumen fluid samples, taken 0, 2, 4, 6 and 8 h after the meal, showed a consistently lower acetate to propionate ratio when feeding PG. Blood insulin was not affected by PG administration. Except for therapeutic treatments, PG administration to dairy cows at mid stage of lactation should be advised against. Despite the positive effect on intake, administration of the additive, increasing the molar percentage of rumen propionate, contributes to shift the energy partition from milk production to liveweight gain.

Technical note: Precision and accuracy of in vitro digestion of neutral detergent fiber and predicted net energy of lactation content of fibrous feeds

The objective of this study was to test the precision and agreement with in situ data (accuracy) of neutral detergent fiber degradability (NDFD) obtained with the rotating jar in vitro system (Daisy(II) incubator, Ankom Technology, Fairport, NY). Moreover, the precision of the chemical assays requested by the National Research Council (2001) for feed energy calculations and the estimated net energy of lactation contents were evaluated. Precision was measured as standard deviation (SD) of reproducibility (S(R)) and repeatability (S(r)) (between- and within-laboratory variability, respectively), which were expressed as coefficients of variation (SD/mean × 100, S(R) and S(r), respectively). Ten fibrous feed samples (alfalfa dehydrated, alfalfa hay, corn cob, corn silage, distillers grains, meadow hay, ryegrass hay, soy hulls, wheat bran, and wheat straw) were analyzed by 5 laboratories. Analyses of dry matter (DM), ash, crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) had satisfactory S(r), from 0.4 to 2.9%, and S(R), from 0.7 to 6.2%, with the exception of ether extract (EE) and CP bound to NDF or ADF. Extending the fermentation time from 30 to 48 h increased the NDFD values (from 42 to 54% on average across all tested feeds) and improved the NDFD precision, in terms of both S(r) (12 and 7% for 30 and 48 h, respectively) and S(R) (17 and 10% for 30 and 48 h, respectively). The net energy for lactation (NE(L)) predicted from 48-h incubation NDFD data approximated well the tabulated National Research Council (2001) values for several feeds, and the improvement in NDFD precision given by longer incubations (48 vs. 30 h) also improved precision of the NE(L) estimates from 11 to 8%. Data obtained from the rotating jar in vitro technique compared well with in situ data. In conclusion, the adoption of a 48-h period of incubation improves repeatability and reproducibility of NDFD and accuracy and reproducibility of the associated calculated NE(L). Because the in vitro rotating jar technique is a simple apparatus, further improvement would probably be obtained by reducing the laboratory differences in rumen collection procedures and type of animal donors, which, however, reflect practical conditions.

Near infrared spectroscopy in animal science production: principles and applications

Abstract Near infrared (NIR) is one of the techniques belonging to vibrational spectroscopy. Its radiation (750 to 2500nm) interacts with organic matter, and the absorption spectrum is rich in chemical and physical information of organic molecules. In order to extract valuable information on the chemical properties of samples, it is necessary to mathematically process spectral data by chemometric tools. The most important part in the development of an NIR method is building the predicting model generally called calibration. NIR spectroscopy has several advantages over other analytical techniques: rapidity of analysis, no use of chemicals, minimal or no samples preparation, easily applicable in different work environments (on/in/at line applications). On the other hand, NIR spectroscopy has some disadvantages: low ability to predict compounds at low concentration (<0.1%), necessity of accurate analysis as reference, development of calibration models required high trained personnel, need of a large and up-to-date calibration data set (often difficult to obtain), difficulties to transfer calibration among instruments, initial high financial investments. In the feed industry, NIR spectroscopy is used for: feed composition, digestibility (in vivo, in vitro, in situ), traceability assessment (to avoid possible frauds). As far as animal products are concerned, NIR spectroscopy has been used to determine the main composition of meat, milk, fish, cheese, eggs. Furthermore, it was also used to predict some physical properties (tenderness, WHC (Water Holding Capacity), drip loss, colour and pH in meat; coagulation ability in milk; freshness, flavour and other sensorial parameters in cheese). Interesting applications of NIR spectroscopy regard issues like: determination of animal products’ authenticity and the detection of adulteration (in order to prevent frauds), discrimination PDO (Protected Designation of Origin) and PGI (Protected Geographical Indication) from other non traditional products, detect handling aspects (freezing, thawing or fresh). There is a growing interest in the evaluation of animal products’ quality directly on-line to have a continuous control of the production process. Furthermore, new portable instruments are becoming now available, which will allow to easily monitor some processes at the factory (i.e. ripening and ageing of sausages and cheeses).

Effects of yeast culture addition on digestion in sheep fed a high concentrate diet

Abstract Effects of yeast culture on intake, rumen parameters, digestibility and passage rate were studied in 12 sheep (average BW 59±3.5 kg). A high concentrate diet was supplemented with 0 (control), 20 (Y20) or 40 (Y40) g/d of yeast. DMI tended to be higher (P

Comparison of Visible and Near-Infrared Reflectance Spectroscopy to Authenticate Fresh and Frozen-Thawed Swordfish (Xiphias gladius L)

This study evaluated near-infrared (NIR) and visible-NIR (Vis-NIR) spectroscopy as a way to distinguish fresh (F) from frozen-thawed (T) swordfish cutlets (Xiphias gladius). A total of 90 F and 60 T samples were used. The T samples were stored at a high and low frozen temperature (HT: −10°C; LT: −18°C). Spectra were collected using a Vis-NIR portable spectrophotometer (380–1080 nm) and a NIR monochromator (1100–2500 nm). The percentage of correctly classified samples obtained with Vis-NIR spectroscopy was ≥ 96.7%, whereas that for NIR was ≥ 90.0%. The best classification was observed comparing F and HT samples using Vis-NIR (100 vs. 96.7%, respectively). The more descriptive principal component scores (PCS) of NIR and Vis-NIR were used with a multivariate binary logistic regression. The model with the PCS of the first two Vis-NIR principal components accounted for 81.1% of the classification. Vis-NIR could be a strategic tool to screen the cold treatment of swordfish.

Effect of unsaturated fatty acid supplementation on performance and milk fatty acid profile in dairy cows fed a high fibre diet.

Abstract The influence of unsaturated fatty acid (UFA) supplement on productive performance, physiochemical properties and fatty acid (FA) profile of milk, was investigated in lactating dairy cows fed with high fibre diets. According to a cross-over design, twelve cows were assigned to two experimental settings characterized by different FA profiles. Cows received a high fibre diet (~42% NDF on DM basis) supplemented with soybean based mixtures with these FA compositions: 92.0% of saturated FA (SFA), 2.8% of monounsaturated FA (MUFA) and 5.2% of polyunsaturated FA (PUFA) in the control diet (C-diet); 19.1% of SFA, 20.9% of MUFA and 60.0% of PUFA in the experimental diet (E-diet). The E-diet did not affect dry matter intake nor milk yield. Milk composition and coagulation traits resulted similar between treatments, except for the lactose level, which was lower in the E-diet (5.0 vs 4.8%; P<0.05) and the freezing point (-0.546 vs -0.535 °C; P<0.05). As respects the milk FA profile, the E-diet significantly increased the percentage of UFA because of their greater amount in the ration; however the “transfer” of UFA in milk was limited by the high level of FA biohydrogenation (BH) at the ruminal level. UFA showed low values of carry over in milk (67.5 vs 39.7%; P<0.001) due to the saturation process; on the contrary SFA had a threefold increment (124 vs 323%; P<0.001), mostly due to a peak in the production of stearic acid. In this study, the percentage of CLA in milk (0.50 vs 0.62%; P<0.05) was quite low for both diets, if compared with other studies, and this was probably due to a low vaccenic acid supply at duodenal level.

Feather and blood meal as partial replacer of soybean meal in protein supplements for sheep

Abstract Effects of partial replacement of soybean meal with a combination of feather and blood meal in protein supplements for sheep were investigated. Four diets based on corn silage were formulated: 100% soybean meal (SBM) vs. 56% soybean meal + 22% feather meal + 22% blood meal (MIX); and two energy levels: 11.0 (MID) vs. 11.8 MJ ME/kg DM (HIGH). The four diets were fed at maintenance to four adult Lamon wethers (83.9 ± 9.9 kg BW) fitted with a ruminal cannula. Overall in-situ protein degradability of SBM and MIX was 81.5 and 61.6%, respectively. Compared to SBM, feeding MIX diets increased ( P